I found plenty of stalls and won’t restart, but that isn’t my case.

New to me 1987 XJ6, 55,000 miles. Everything looks original.

First instance the car/engine was cold, going about 30 mph and the car cuts off. I didn’t see any dash lights come on. Put the car in neutral while still coasting and restarted immediately, put back in gear and no issues.

Second instance the car was fully warmed up going about 45 mph and the same scenario. Car shuts off, put in neutral and restarts immediately. No further issues for the next 20 miles or so.

Other things I doubt are related but… not sure on fuel tanks and senders. Switch pushed in reads empty, out reads just above empty, but that’s it. I’m thinking possible rusted senders.

Causes? Bad or going bad coil? Mine looks original.

Bad and or going bad contacts in ECU?

Fuel issues if rusted fuel tanks?

it has happened twice now in about 125 miles.

 

Drove an hour this morning and it didn't stall. Perplexing. First thing taking off I did step on the gas and the motor stumbled, like it was starved for fuel. Motor had yet to warm up. Once up to full temperature the motor was smooth as silk. Bad cold start injector? I wouldn't think if it was bad that it would start immediately when cold, which the car does.

I think I will start with the fuel system. Have the injectors rebuilt, new fuel tanks with senders, fresh fuel filter, etc... I just bought a Pertronix module for the ignition amplifier. Car has new plugs, plug wires, cap and rotor. I will clean all contacts as best as possible and go from there. I have a spare ECU I could swap, but not sure if that is needed just yet.

 

Have a read of this information assembled by Roger Bywater of AJ6 Engineering:

Fuel injection and the Jaguar XJ6 4.2 Series 3 / AJ6 Engineering

 

I read all of that and still not sure what would be the cause. I have a spare XJ that I could swap ECUs, coil, sensors, etc.. but it would be nice to have a general idea what would cause the car to do this, fuel issues or electrical.

Looks like someone has been inside the ignition amplifier at some point.

 

Replace the NAPA module with an AC Delco D1906.

A few years ago I was in a pinch and used a NAPA module and had problems almost right off the bat. And I'm not alone. Over the decades others have reported problems with alternate brands.

No promises....but worth a try.

Cheers
DD

 

If you are replacing NAPA module, also disable the capacitor and the clamping diode from the circuit; Neither are not needed: capacitor is for radio noise and diode is to protect the weakness of the original module from over voltage. All current 4 pin modules have internal protection.

New coil that is a match for new Pertronix module should be installed. Lucas # DLB198 or Pertronix 45111 Ignition Coil.

Yes this is trouble shooting by parts replacement, but these parts are all suspect and have a history of intermittent operation.
Rgds
David

 

Haven't been able to come to terms with the Neutral Restart... Seems only thing common is electrical portion of ignition switch, which have known to give up with age.

Everything fine with ignition switch in # 3 position, suddenly engine dies. Fix move shift lever to neutral and move ignition switch to #4 and you have instant restart.. switch back to #3 position and shift lever back to Drive. All good for another 30 minutes.

Follow lead from #3 ignition switch to (-) terminal on ignition coil, insure that all connectors are good (tight) and no corrosion, If good, and ground wires at the back of intake manifold and back of water cooling manifold are good, then I would throw the electric portion of the ignition switch in the possibility column.

Others with more experience with ignition switch issues and possibility that it would cause your problem.
Rgds
David

 

My 20 cents worth suggests the ignition switch.
I had a similar problem in a Series 2 XJ6

 

When I had a similar sort of problem with my Daimler, it turned out to be ground connections. Make sure any/all ground straps to the engine block are present, in good condition, and soundly connected at both ends.

 

All great advice, I used a Pertronix module. I also have a Pertronix distributor that has never been used from a previous XJ6 build, would this be an upgrade to the stock distributor? This would be wired directly to the coil and eliminate the ignition amplifier? I assume at 56,000 miles the one in the car is in fine condition.

Though this issue does seem electrical, I did change the fuel filter and the fuel that came out of it was not good. It was rusty brown in color, so the fuel tanks will be replaced. I have a feeling this car may have sat in storage for long periods of time without the tanks being topped off and now that I am using it rust that developed is getting mixed up in the gas.

 

" I used a Pertronix module. I also have a Pertronix distributor that has never been used from a previous XJ6 build, would this be an upgrade to the stock distributor?"

There are several levels of performance with Pertronix modules and depending which is in your distributor, it may not be an upgrade to your OEM electronic ignition system.
If you have the Ignitor I module in your OEM distributor or the Pertronix distributor, this is for Carbureted Jaguar engines and would be a down grade for a S3 fuel injected engine.
For XJ6 S3 you need Ignitor II. If you have an early D177600 Pertronix distributor, you can upgrade it by replacing the pickup with a Ignitor II pickup.
If you install the Pertronix distributor, you definitely wire it directly to the coil. If you remove "Lucas Ignition Amp" front the front of your intake manifold you must plug the mounting holes to prevent intake leak. 3/4" long bolt same size & thread as mounting bolt works.

Another thought about cut out.. the fuel injector resistance pack on RH wheel well has common ground for all injectors. Remove connector at bottom of resistor pack and clean with contact cleaner and re- install 3 times to ensure good contact. Then follow ground wire(s) to where it they connected to engine or body and clean and reinstall terminal.
Rgds
David

 

The Pertronix module and distributor are the newer ones specifically for the Series 3. Clearly the module would no longer be needed if I install the Pertronix distributor.